package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock {

    private String name;

    private StringRedisTemplate stringRedisTemplate;

    private static final String KEY_PREFIX = "lock:";
    private static final String ID_PREFIX = UUID.randomUUID().toString(true) + "-";
    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;

    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }

    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    @Override
    public boolean tryLock(Long timeoutSec) {

        String threadId = ID_PREFIX + Thread.currentThread().getId();

        Boolean aBoolean =
                stringRedisTemplate
                        .opsForValue()
                        .setIfAbsent(KEY_PREFIX + name, threadId, timeoutSec, TimeUnit.SECONDS);
        return Boolean.TRUE.equals(aBoolean);
    }

    /**
     * 基于lua脚本
     */
    @Override
    public void unLock() {
        stringRedisTemplate.execute(
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX + name),
                ID_PREFIX + Thread.currentThread().getId());
    }
    //    /**
    //     * 还是会出现误删lock问题
    //     */
    //    @Override
    //    public void unLock() {
    //
    //        //获取线程标识，与redis中值比对
    //        String threadId = ID_PREFIX + Thread.currentThread().getId();
    //        String lockId = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
    //        if (threadId.equals(lockId)){
    //            stringRedisTemplate.delete(KEY_PREFIX + name);
    //        }
    //    }
}
